<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
	</body>
	<script>
		class Father {
			constructor(x,y) {
			    this.x = x;
				this.y = y;
			}
			sum() {
				console.log(this.x+this.y);
			}
		}
		
		class Son extends Father{
			constructor(x,y) {
				super(x,y);
			    this.x = x;
				this.y = y;
			}
			subtract() {
				console.log(this.x - this.y)
			}
		}
		var son = new Son(5,3);
		son.subtract()
		son.sum()
	</script>
</html>
